Continuing the discussion from Laser Cutter - Trotec Speedy 300:
Dear interested parties,
I am a little confused why MDF is on the banned list of materials.
Apart from acrylic (which is at least 4x the cost), 3 to 6mm MDF is usually the backbone of craft and prototype lasercutting in my limited but international experience.
Sources indicating it can be cut;
- Trotec. Specifically, here: http://www.troteclaser.com/en-US-GB/Materials/Pages/Wood.aspx
- London Hackerspace on their old (inferior to the Speedy I would hope) and scrapped machine: https://wiki.london.hackspace.org.uk/view/Equipment/HPC_LS3060_Laser_Cutter
- London Hackerspace on their new, equivalent machine: https://wiki.london.hackspace.org.uk/view/Silvertail_A0_Laser_Cutter#Allowed
- ATX hackerspace; http://www.atxhackerspace.org/wiki/Laser_Cutter_Materials
- Edinburgh hacklab (who also sell MDF); http://wiki.edinburghhacklab.com/lasercutter
- Hacman (Manchester) and Build Brighton do not specifically exclude MDF
I think that the main rationales for Forbidding materials would presumably be that they are known to either;
- Pose an unacceptable risk of fire or damage to the equipment
- Generate known dangerous fumes which exceed our ability to ventilate
An example of the former would be styrene or polystyrene; it tends to melt and catch fire rather than cut or engrave, and has destroyed many other space’s cutters
An example of the latter would be chlorinated plastics, such as Polyvinyl Chloride (“vinyl” and “PVC”)
Some materials may need additional precautions; for example,
- Many woods (including hardwoods) may be oily and pose additional fire risk
- Engineered materials (Plywood, MDF) which often have glues mixed in; these are not necessarily dangerous but can cut poorly compared to (for instance) pure birch
- Rubber, which may or may not contain chlorine
- Multi-component items like foam core and Depron, where different layers burn at different rates
- Many cloths and leathers can be cut or etched, but again some materials must be avoided for fire or fume reasons (e.g. “pleather”)
Qualifiers like “Laser Grade” Plywood should probably be avoided.
Although it may indicate that it cuts better than a plywood with thicker glue or different wood, blanket exclusion of non- “laser grade” materials is misleading.
Materials of similar quality but sold from non-laser shops can meet or exceed expectations. Specifically, there is no one quality that defines a plywood as “laser grade” - it is a combination of the exterior and interior layers quality, grain, thickness, number of knots; the number of layers; the amount and type of glue (phenolic glues take 4x as long to cut);
I would highly recommend reading this blog post from a small-scale manufacturer who do this all the time. Their puzzles are cool
Some materials cut so poorly that warning makers against use is necessary
Materials that do not pose an equipment safety or toxic fume risk are reasonable to list as a “does not cut”, for example;
- Polycarbonate; tends to warp and discolour
- Gold coated mylar, IR reflective surfaces (Like copper on PCB)
This is not to say that it can’t be cut; I have personally etched PCBs using a laser cutter and spray-on paint, and some reflective surfaces like the backs of common, non-first-surface) mirrors can be etched off to great effect.
Why MDF might not be cut in the space
I obviously don’t know the full story here. But here are some concerns I can guess;
- MDF fibres are believed to cause a health risk
- Partially true. They mostly pose an issue with chronic exposure (i.e. professional)
- Yes, there is generally formaldehylde in MDF. The amount is extremely limited if you buy your MDF in the EU
- Almost all the risk comes softwood and hardwood particulate matter, which comes from sanding and machining MDF, not burning it
- Local exhaust ventilation and vacuuming with a HEPA filter equipped vacuum cleaner is the general requirement
- Please read This helpful FAQ from your government
- The experience on the previous iteration of our laser cutter was unsatisfactory / it did not cut
- But surely this is an issue with either the setup, or an issue of “does not cut” rather than “forbidden from cutting”.
- Do trotted really want public documentation that they have supplied the only lasercutter in the UK that I can find upon which MDF is Forbidden?
- It smells bad / awful
- But so does brewing beer, and we haven’t complained to the council about Canopy yet
- Bad smell does not mean a toxic fume issue. Gangrene smells bad. Sewerage smells bad. Low levels of hydrogen sulphide (up to about 10ppm) smell Awful. None of those smells pose any toxic, fume related effects.
- The reasoning for forbidding MDF be put forward and debated, and documented.
- In the absence of meeting an agreed threshold for being forbidden, the status of MDF be revised to;
- MDF up to 4mm be listed on the “Permitted materials” list
- MDF from 5 - 18mm be listed as “Use with additional precautions (Fire risk)”
- MDF >18mm be listed as “Does not cut” (But can be engraved)